The present invention relates to a combustion chamber apparatus.
The combustion chamber apparatus of the present invention may be used for the ignition of solid fuels in covered kettle cookers and other barbeque apparatus. Covered kettle cookers and barbeques use solid fuels in the form of charcoal and/or fuel briquettes formed of compressed char or charcoal. To ignite the solid fuels it is common practice to place one or more lighted firelighting cakes in the base of the cooking apparatus and place solid fuel on top. Heat and flame from the firelighters eventually causes the solid fuel to ignite. Cooking commences when the solid fuel reaches the desired temperature and will maintain a sustainable fire. It is not uncommon for the process of igniting the barbecue fuel and attaining the desired temperature to take up to 45 minutes or longer.
Moreover, the firelighters used to promote the ignition of the beads are traditionally based on solid hydrocarbons. The covering of the firelighter with solid fuel often leads to there being insufficient air space available for complete combustion of the firelighter leading to the production of quantities of smoke composed of unburnt fuel air mixture, and unreliable ignition as the flames from the firelighter are often extinguished. Thus, further time may pass before cooking may commence.
A number of earlier devices have been proposed to enable charcoal and other fuels to be heated and fires to be started in outdoor cooking equipment. Such devices are exemplified in U.S. Pat. Nos. 3,841,299 (Tomita), U.S. No. 3,915,145 (Tomita), U.S. No. 4,026,265 (Spadaro) and U.S. No. 3,848,577 (Storanolt). A further example may be formed in FR 2587788 (Michel). Each of these documents discloses a generally cylindrical chamber with a combustion chamber in the lower part of the cylinder and an upper charcoal chamber. A flat grate separates each of the chambers and charcoal rests on the grate.
The devices disclosed in each of the above suffer from a number of defects which adversely affects their utility and has prevented their adoption by the general public. In general, the prior art devices mentioned do not operate efficiently and substantial quantities of firelighting material or firelighting cakes are generally required to encourage the charcoal or fuel to burn. This may result in tainting of the food and increases the cost of operating the apparatus.
The inefficiency of the prior art devices may generally be attributed to the poor transfer of heat from the firelighting material to the charcoal or other fuel which occurs. The burning firelighting material may be considerably distanced from the charcoal giving rise to difficulties with producing a high enough temperature to instigate burning in the charcoal.
The devices described in the prior art have been arranged this way to ensure that air is able to circulate freely around the firelighting cakes. The designs are thus a compromise between providing sufficient air to burn a firelighting cake without danger of extinction by smothering the fire, whilst at the same time having the charcoal or other fuel in a suitable position to be ignited.
The prior art devices also have a number of drawbacks in the safety of their operation. Namely, that when in use, the devices described contain the hot charcoal or fuel beads which may have to be transferred manually to a separate cooker. This generally occurs by lifting the container together with the coals and inverting into the cooker. This operation is potentially hazardous and accidental spillage of hot fuel could result in serious injury to those in the immediate area.
A further problem arises when the prior art devices are operated in windy conditions or where the fuel used is very dusty. The prior art devices are commonly arranged such that it is relatively easy for dust from the charcoal or fuel beads to be transferred through a grate onto a firelighting cake. This can impede the burning of the cake or further hamper the cake of the device as a whole.